By Joseph A. Califano Jr.

If ever there were a moment for President Obama to learn from history, it is in the wake of the school shootings in Newtown. The lesson to be drawn from Lyndon B. Johnson is this: Demand action on comprehensive gun control immediately from this Congress or lose the opportunity during your presidency.

In the aftermath of the assassination of Robert F. Kennedy (just weeks after the fatal shooting of Martin Luther King Jr. and only a few years after President John F. Kennedy was shot), Johnson pressed Congress to enact gun-control legislation he had sent to Capitol Hill three years earlier. LBJ ordered all of us on his staff - and urged allies in Congress - to act swiftly. "We have only two weeks, maybe only 10 days," he said, "before the gun lobby gets organized." He told Larry O'Brien and me, "We've got to beat the NRA [National Rifle Association] into the offices of members of Congress."

LBJ was always poised to grasp any opportunity to achieve his legislative objectives. He had used the tragedy of King's assassination in 1968 to "at least get something for our nation" out of it, finally persuading the House to pass the fair-housing bill he had sent it in 1966. Johnson saw in the assassination of RFK a chance to get his gun bill enacted.

Johnson's bill would ban all mail-order and out-of-state sales of handguns, shotguns, and rifles; prohibit the sale of guns to minors; and require national registration of all guns and licensing of all gun owners. There had been little hope of enactment. But the day after Kennedy died from gunshot wounds in June 1968, LBJ renewed his pressure on the Senate Judiciary Committee to report his bill out and send it to the Senate floor for a vote.

Maryland Sen. Joseph Tydings, a close friend of Kennedy, and a couple of Democratic colleagues wanted the committee to consider a bill they believed was stronger. LBJ thought the Tydings proposal had no chance of passage and feared that any delay to consider it would give the gun lobby time to kill all or part of his legislation.

That's exactly what happened. The Tydings proposal never got beyond the discussion phase, and LBJ's comprehensive bill failed by a tie vote in the committee. With relentless pressure, he was able to get a bill by October with a prohibition against mail-order sales, sale of guns to minors, and importation of "$10 specials" (cheap guns that were pouring into the country). But Johnson's pet proposals to license all gun owners and register all guns were defeated.

When he signed the legislation on Oct. 22, 1968, LBJ vented his anger with the gun lobby for killing licensing and registration:

"The voices that blocked these safeguards were not the voices of an aroused nation. They were the voices of a powerful gun lobby, a gun lobby that has prevailed for the moment in an election year. ... We have been through a great deal of anguish these last few months and these last few years - too much anguish to forget so quickly. So now we must complete the task which this long-needed legislation begins."

Obama's pained remarks in the wake of the latest school shooting echo Johnson's anguish a half-century ago. But Obama has a unique opportunity: a lame-duck session of Congress. If he learns from the lesson of LBJ - two weeks to get action - and takes advantage of the fact that many members can vote their conscience without fear of retribution by the gun lobby because they are not seeking reelection, this nation may "complete the task" of passing comprehensive gun controls. That's an opportunity that is worth grasping out of the unspeakable tragedy that occurred in Newtown.